Tuesday, November 14, 2006

Virtual Reality phantom limb eases pain for amputees...

It was bound to happen sooner or later. After mirror therapy (citation below) to treat phantom limbs, it seems that they have finally perfected a technique to treat this condition using virtual reality...
Read on more at http://news.bbc.co.uk/2/hi/health/6146136.stm

From the Glaxo Wellcome page I got this information that explains the malady a little better..

"Phantom limb pain – pain appearing to come from where an amputated limb used to be – is often excruciating and almost impossible to treat.After amputation of a limb, an amputee continues to have an awareness of it and to experience sensations from it. These phantom limb sensations are also present in children born without a limb, suggesting that perception of our limbs is 'hard-wired' into our brain and that sensations from the limbs become mapped onto these brain networks as we develop.

If phantom limb sensations are normal then so too, alas, is phantom limb pain. This occurs in a majority of those who lose their limbs. In fact, limbs do not need to be lost; it also occurs in conditions in which the brain is disconnected from the body, such as peripheral nerve injuries and after spinal cord injury, when an area becomes insentient (and usually paralysed).

"Evidence that stimulation of the motor cortex (the area that controls movement) can reduce phantom limb pain has been around for some time. Perhaps more surprising was a trial by Ramachandran and Rogers-Ramachandran . They asked people with amputations of the arm and phantom limb pain to place their arms inside a mirror box so that they saw their remaining arm mirror-reversed to look like their amputated one. When they moved their remaining arm in the box they were 'fooled' into thinking they were moving their amputated one, and their pain was reduced. Although this has proved less effective in some subsequent trials, it did suggest that phantom limb pain might reflect a loss of motor control to the limb, as well as loss of sensory input from it.

More recently the mirror box has been used with some success in pain that is not due to sensory loss. In fact, a box may not be required. In phantom limb pain due to a peripheral nerve injury (brachial plexopathy), the authors have shown that merely training patients to imagine their paralysed arms moving in relation to a moving arm on a screen in front of them can relieve phantom limb pain.

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